1. Field of Invention
The present invention relates to a projector including a light source, an optical modulation device for modulating a luminous flux emitted from the light source according to image information, and a projection lens for enlarging and projecting an image formed by the optical modulation device.
2. Description of Related Art
Hitherto, projectors have been used which include a light source, an optical system for forming an image by a luminous flux emitted from the light source according to image information, and a projection lens for enlarging and projecting the image formed by the optical system onto a projection plane. The optical system consists of an illuminating optical system for producing a uniform in-plane illumination distribution of a luminous flux emitted from the light source, a color separation optical system for separating the luminous flux from the illuminating optical system into three primary colors of red, blue, and green, an optical modulation system including an electro-optical apparatus for modulating color luminous fluxes according to image information, and a color-synthesizing optical system for synthesizing modulated color luminous fluxes. The electro-optical apparatus includes three optical modulation devices for modulating each of a red luminous flux, a blue luminous flux and a green luminous flux separated by the color separation optical system according to image information. For example, a liquid crystal panel using a polysilicon TFT as a switching element is used.
Since the optical modulation devices are important portions for forming an optical image according to image information, if dust or oil mist adheres to the surface of the liquid crystal panel, the image quality of the projector will deteriorate. For this reason, a projector including an enclosing structure for enclosing an optical path from the optical modulation devices to the projection lens may be adopted. Since such a projector can prevent the entry of dust or oil mist from the outside by the enclosing structure, dust or oil mist does not adhere to the surface of the liquid crystal panel of the optical modulation device, and the image quality of the projector can be stably secured over a long period of time. Such a projector is suitably used as a stationary projector, such as a hanging-type projector.
However, since the optical modulation device, such as the liquid crystal panel, is easily affected by heat, if the optical path from the optical modulation device to the projection lens is enclosed by the enclosing structure, it is difficult to efficiently cool the optical modulation device by introducing cooling air from the outside. In particular, in a recent trend toward an increase in brightness and a reduction in size of the projector, efficiently cooling the optical modulation device is an important problem.
On the other hand, the electro-optical apparatus is usually mounted on a structure to which the projection lens is attached. Thus, in order to enclose an optical path from the electro-optical apparatus to the projection lens, a large enclosing structure for enclosing the electro-optical apparatus and the structure is required, and it is therefore difficult to reduce the size of the projector.
It is an aspect of the present invention to provide a projector capable of efficiently cooling an electro-optical apparatus, and of stably securing the image quality for a long period of time.
It is another aspect of the present invention to provide a projector capable of preventing dust from adhering to an electro-optical apparatus by enclosing an optical path from the electro-optical apparatus to a projection lens, and of reducing the size of the device.
According to the first aspect of the present invention, there is provided a projector having a light source, an electro-optical apparatus for modulating a luminous flux emitted from the light source according to image information, and a projection lens for enlarging and projecting an image formed by the electro-optical apparatus, the projector may include an enclosing structure for enclosing an optical path from the electro-optical apparatus to the projection lens, and an air circulation path for circulating air of the enclosing structure, wherein the air circulation path is disposed in a flow path for cooling air formed inside the projector.
The enclosing structure can be formed by a box-like member for sealing and accommodating therein the electro-optical apparatus. The box-like member made of metal, such as magnesium alloy, may be adopted. In addition, the air circulation path can be formed by, for example, a pipe-like member connected to the upper portion of the enclosing structure at one end thereof, and connected to the lower portion of the enclosing structure. In short, the air circulation path may have a structure such that it can circulate air inside the enclosing structure from above to the below, or from below to above while holding sealing performance of the enclosing structure. Furthermore, in order to circulate internal air, a forcible circulation device, such as a fan, may preferably be provided inside the enclosing structure. As the forcible circulation device, a common axial flow fan can be adopted. However, a centrifugal fan for exhausting air drawn by the rotation of the fan in the direction tangential to the rotation may preferably be adopted.
According to the present invention, since the air circulation path is disposed in a flow path for cooling air formed inside the projector, the air circulation path is cooled and the air flowing in the air circulation path is cooled. The cooled air inside the air circulation path circulates inside the enclosing structure, whereby the electro-optical apparatus can be efficiently cooled. In addition, since the air for cooling the electro-optical apparatus circulates only in the enclosing structure and the air circulation path, dust or oil mist does not enter from the outside, and image quality of the projector can be stably secured for a long period of time.
In the foregoing, the air circulation path may preferably be formed by a metal pipe-like member. Since the pipe-like member made of metal, such as copper, aluminum or the like, has high heat-radiating performance, air inside the air circulation path can be further efficiently cooled if it is disposed in the flow path for cooling air inside the projector. In addition, when the above-described centrifugal fan is adopted as the forcible circulation device, the air inside the enclosing structure can be sufficiently circulated by the centrifugal fan, considering the length of the flow path of the air circulation path in which discharge pressure of the centrifugal fan is substantially equal to the area of the air outlet of the centrifugal fan. In this case, the inside diameter of the pipe-like member may preferably be set at 10 mm to 30 mm.
In addition, the air circulation path may preferably be detachable to the enclosing structure and the air circulation path and the enclosing structure may preferably be connected via a seal material. In this way, since the enclosing structure and the air circulation path are detachable, maintenance of the electro-optical apparatus inside the enclosing structure can be easily carried out. In addition, since the air circulation path and the enclosing structure is connected via the seal material, it is possible to securely prevent air leakage inside the enclosing structure. Furthermore, even if the enclosing structure and the air circulation path are made of different metals such that the material of the enclosing structure is a magnesium alloy and the material of the air circulation path is aluminum, since they are connected by the seal material, such as rubber, electrolytic corrosion does not occur at a joint portion between two different metals, and sealing performance of the enclosed structure can be permanently secured.
Furthermore, the air circulation path may include a radiating structure for releasing heat inside the air circulation path to the outside. Here, the radiating structure may be composed of a plurality of radiating fins extending toward the outside of the radial direction of the air circulation path. In addition, as another example, a radiating structure constructed by spirally winding a linear material comprising a linear core member and a plurality of radiating pieces projected toward the outside of the radial direction of the core member around the air circulation path may be adopted.
Since the air circulation path includes the radiating structure, if the air circulation path is disposed in the flow path for cooling air inside the projector, air inside the air circulation path can be more effectively cooled by the cooling air.
Furthermore, the air circulation path may preferably be disposed aside the projection lens. Since such a projection lens has an optical adjusting mechanism, such as zooming or focusing, the length of the projection lens is elongated and a dead space tends to be formed aside the projection lens. Therefore, if the air circulation path is disposed aside the projection lens, it is possible to provide a tight inner structure of the projector, and the projector is advantageously reduced in size.
A cooling fan for cooling the inside of the projector may preferably be provided in the vicinity of the air circulation path. Here, the cooling fan is not limited to a special one for spraying cooling air to the air circulation path, and may be a cooling fan provided to cool other portions of the projector.
In this way, since the cooling fan is provided in the vicinity of the air circulation path, the air circulation path can be further efficiently cooled by forcible introduction or exhaustion of the cooling air effected by the cooling fan.
According to another aspect of the present invention, there is provided a projector having a light source, an electro-optical apparatus for modulating a luminous flux emitted from the light source according to image information, and a projection lens for enlarging and projecting an image formed by the electro-optical apparatus, the projector may include an enclosing structure for enclosing an optical path from the electro-optical apparatus to the projection lens; and an air circulation path connected to the enclosing structure, and circulating air inside the enclosing structure, wherein a circulating fan for flowing air inside the enclosing structure to the air circulation path is disposed inside the enclosing structure.
In this way, since the circulating fan is provided inside the enclosing structure, it is possible to forcibly circulate air inside the enclosing structure through the air circulation path. Therefore, by making thermal exchange between the air circulating inside the enclosing structure and the electro-optical apparatus, the electro-optical apparatus can be efficiently cooled. In addition, since the electro-optical apparatus is enclosed by the above-described enclosing structure, dust or the like does not adhere to the electro-optical apparatus, and the image quality can be stably secured for a long period of time.
In the foregoing, the circulating fan may preferably be a centrifugal fan for exhausting air drawn by the rotation of the fan in the direction tangential to the rotation. In this way, by adopting the centrifugal fan, high pressure of the air when exhausted can be obtained and therefore, the air inside the enclosing structure can be securely circulated using the magnitude of the discharge pressure. In addition, since the centrifugal fan generates high discharge pressure as compared with a normal axial flow fan, noise produced by the rotation of the fan can be minimized by rotating the fan at low speed.
In addition, the enclosing structure may preferably have an electro-optical apparatus placing portion for placing the electro-optical apparatus, and the centrifugal fan may preferably be disposed above the electro-optical apparatus, and an intake surface thereof may oppose the electro-optical apparatus placing portion. In this way, since the centrifugal fan is disposed above the electro-optical apparatus, and the intake surface thereof opposes the electro-optical apparatus placing portion, the electro-optical apparatus is disposed in the air circulating flow on the side of the intake portion of the centrifugal fan, it is possible to uniformly cool the electro-optical apparatus.
Furthermore, the enclosing structure may preferably have a projection-lens mounting portion for mounting thereto the projection lens, a flange projecting toward the outside of the radial direction of the projection lens may preferably be provided at the base end of the projection lens, and the flange and the projection-lens mounting portion are joined, whereby the projection lens is mounted to the enclosing structure, and the centrifugal fan may preferably be disposed at a portion corresponding to an inner area of the outer peripheral edge of the flange in the radial direction so as not to project toward the outside of the radial direction of the outer peripheral edge of the flange.
If the centrifugal fan is disposed in this way, it is possible to prevent the centrifugal fan from projecting to the outside of the flange, and by reducing the size of the enclosing structure, the projector can be reduced in size and thickness.
In addition, the air circulation path may preferably be composed of a pipe-like member connected to an air outlet of the centrifugal fan at one end thereof, and connected to a lower portion of the enclosing structure at the other end thereof. In this way, since the pipe-like member constituting the air circulation path is connected to the air outlet of the centrifugal fan, while air that has cooled the electro-optical apparatus and has been drawn by the centrifugal fan circulates in the pipe-like member constituting the air circulation path. Therefore, if the pipe-like member is disposed in the flow path for the cooling air inside the projector to perform cooling, the air inside the enclosing structure can be efficiently cooled by heat exchange between the pipe-like member and air. By ejecting the cooled air from the connecting portion of the other end of the air circulation path, the electro-optical apparatus can be cooled.
The electro-optical apparatus may include a plurality of optical modulation devices for modulating the luminous flux according to the image information, and a straightening plate for dividing air ejected from the air circulation path according to the layout of the plurality of optical modulation devices may preferably be provided inside the enclosing structure. Since the straightening plate is provided in this way, the air cooled in the air circulation path can be guided according to heating condition of the plurality of optical modulation devices, and the electro-optical apparatus can be further efficiently cooled.
In addition, the plurality of optical modulation devices may preferably be a red optical modulation device, a green optical modulation device, and a blue optical modulation device for modulating each of a red luminous flux, a green luminous flux, and a blue luminous flux. The straightening plate may preferably be constructed so as to guide the air ejected from the air circulation path in the order of the blue optical modulation device, the green optical modulation device, and the red optical modulation device.
The ranking of heating value of the above-described optical modulation devices, from highest to lowest is the blue optical modulation device, the green optical modulation device, and the red optical modulation device. Therefore, if the air from the air circulation path is guided in the above order, it is possible to suitably cool each of the optical modulation device according to demand.
Furthermore, the electro-optical apparatus may preferably include an optical modulation device for modulating the luminous flux according to the image information, and a clearance of 1 mm to 5 mm may preferably be formed between the enclosing structure and the optical modulation device. In this way, if this degree of clearance is formed between the enclosing structure and the optical modulation device, the air inside the enclosing structure can be suitably circulated along the clearance, thus making it possible to further efficiently cool the electro-optical apparatus. When the clearance size is set at 5 mm or more, the velocity of air flowing in the clearance decreases and the optical modulation device cannot be efficiently cooled, while setting the clearance size at 1 mm or less makes it difficult to manage layout accuracy of the side plates and the optical modulation device. Therefore, the clearance size may preferably be set at 1 mm to 5 mm.
According to still another aspect of the present invention, there is provided a projector having a light source, an electro-optical apparatus for modulating a luminous flux emitted from the light source according to image information, and a projection lens for enlarging and projecting an image formed by the electro-optical apparatus. The projector may include an enclosing structure for enclosing an optical path from the electro-optical apparatus to the projection lens, wherein the enclosing structure is provided with a cooling structure for cooling internal air.
Here, the cooling structure may preferably be formed of, for example, a plurality of cooling fins provided on the outer peripheral portion of the enclosing structure, a Peltier element, and a graphite sheet. Since such a cooling fin, peltier element, and a graphite sheet have high thermal conductivity and heat radiation, it is possible to cool the electro-optical apparatus by cooling the entire enclosing structure so as to cool air therein by a cooling fan or the like provided inside the projector.
Among them, the cooling fin may preferably include a metal base plate, and a plurality of columnar projections projected on the base plate. By adopting the cooling fin as described above, external air is drawn in as cooling air. If the cooling fan is disposed above the enclosing structure and directly below the intake fan, a large surface area of the columnar projections contacting the cooling air is maintained, heat is actively radiated to the cooling air, whereby cooling efficiency is increased. Furthermore, since the cooling air abutted against the base plate flows out in random directions by the valleys formed among the columnar projections, the enclosing structure disposed below the columnar projections can be uniformly cooled.
The cooling structure may preferably be composed of a Peltier element provided on the outer periphery of the enclosing structure. In this way, by providing the Peltier element having high thermal conductivity on the outer periphery of the enclosing structure, heat accumulated in the enclosing structure can be quickly absorbed, and the enclosing structure can be effectively cooled.
In addition, a circulating fan for circulating air inside the enclosing structure may preferably be provided above or below the electro-optical apparatus, and the Peltier element may preferably be provided on the outer periphery of the enclosing structure located on the opposite side of the circulating fan across the electro-optical apparatus. Since the Peltier element is provided in this way, air inside the enclosing structure is sent by the circulating fan to a portion where the Peltier element is provided after cooling the electro-optical apparatus. Therefore, heat exchange is quickly made between the air inside the enclosing structure after cooling the electro-optical apparatus and the Peltier element through the enclosing structure, whereby cooling efficiency of the air inside of the enclosing structure is increased.
Furthermore, the circulating fan may preferably be provided above the electro-optical apparatus, and may include a metal outer casing for accommodating components of the projector including the electro-optical apparatus, and the Peltier element may preferably be provided on the lower surface of the enclosing structure, and be fixed to the inner surface of the outer casing by a thermal conductor having adhesive property. In this way, since the circulating fan is provided above the electro-optical apparatus, and the Peltier element is fixed between the enclosing structure and the metal outer casing by the thermal conductor having adhesive property, the heat accumulated in the enclosing structure is securely and quickly transmitted to the outer casing via the Peltier element, and the overall external casing has the function of cooling fin, whereby the enclosing structure can be efficiently cooled.
The cooling structure may preferably be composed of a graphite sheet connected to the enclosing structure at one end thereof, and connected to a metal part constituting the projector at the other end thereof. In this way, the graphite sheet connected to the metal part of the projector has high thermal conductivity, and the heat of the enclosing structure is transmitted to the metal part via the graphite sheet, whereby the enclosing structure can be efficiently cooled.
In addition, the projector may preferably further include a metal outer casing for accommodating components of the projector including the electro-optical apparatus, and the graphite sheet may preferably be disposed between the lower surface of the enclosing structure and the inner surface of the outer casing in an urged state with a platelike material bent. In this way, since a sheet of the graphite sheet is disposed between the enclosing structure and the outer casing in an urged state, adhesion of both members can be secured without using a bonding agent or the like, and assembling work can be simplified.
Furthermore, a recess for accommodating the graphite sheet may preferably be formed in the inner surface of the outer casing on which the graphite sheet is disposed. In this way, since the graphite sheet is accommodated on the bottom surface of the recess whose height is lower than the periphery by one step, the graphite sheet does not shift during assembly, and assembling work can be further facilitated.
The projector may preferably further include an intake fan for guiding external air to the inside of the device as cooling air, and a cover member for guiding the cooling air drawn by the intake fan to the outer peripheral portion of the enclosing structure, the graphite sheet may preferably have an upstanding surface formed by bending a part of an edge of a platelike material, and be disposed on the upper surface of the enclosing structure, and the upstanding surface may preferably be connected to the cover member. In this way, since flowing of the cooling air toward the projection lens is controlled by the upstanding surface, the enclosing structure can be efficiently cooled.
According to another aspect of the present invention, there is provided a projector having a light source, an electro-optical apparatus for modulating a luminous flux emitted from the light source according to image information, and a projection lens for enlarging and projecting an image formed by the electro-optical apparatus. The projector may include an enclosing structure for enclosing an optical path from the electro-optical apparatus to the projection lens; and an optical component housing for accommodating and disposing optical components, such as a lens and a mirror, and disposed adjacent to the enclosing structure, wherein an intake fan for drawing external air to the inside of the projector is disposed above the enclosing structure, and a cooling-air introduction path for guiding cooling air drawn by the intake fan is formed in a boundary of the enclosing structure and the optical component housing.
In this way, since the cooling-air introduction path is formed, the overall enclosing structure can be cooled by the cooling air drawn by the intake fan, the air inside the enclosing structure can be further efficiently cooled together with the above-described air circulation path, thus making it possible to prevent temperature rise of the optical modulation device.
In the foregoing, the cooling-air introduction path may preferably be a clearance formed along a boundary of the enclosing structure and the optical component housing, and the clearance size may preferably be set at 1 mm to 10 mm. If the cooling-air introduction path is formed in this way, the cooling-air introduction path can be constructed without separately providing a duct or the like. Therefore, the inner structure of the projector can be simplified, and cooling efficiency can be maintained by the cooling-air introduction path.
In addition, a cover member may preferably be provided between the boundary of the optical component housing along the cooling-air introduction path and the intake fan so as to surround the cooling-air introduction path. In this way, since the cover member is provided, it is possible to necessarily and sufficiently guide the cooling air from the cooling fan to the cooling-air introduction path, thus further increasing cooling efficiency of the enclosing structure.
Furthermore, the projector may preferably further include a driving circuit board disposed above the optical component housing to drive the electro-optical apparatus, and a cooling-air introducing opening for partially guiding cooling air from the cooling fan to the driving circuit board may preferably be formed in the cover member. Here, the size of the cooling-air introducing opening can be suitably set according to the size of the driving circuit board and heating condition of the circuit element mounted thereon during driving. That is, since the cooling-air introducing opening is formed in the cover member, the cooling air from the intake fan can be partially guided to the driving circuit board to be cooled, making it possible to suitably cool the heating portion inside the projector.
The projector may preferably further include an outer casing for accommodating therein the optical component housing and the electro-optical apparatus, and an exhaust fan for exhausting air inside the outer casing to the outside, and an exhausting flow path for guiding cooling air cooled the enclosing structure to the exhaust fan may preferably be provided between the lower surface of the optical component housing and the inner bottom surface of the outer casing. In this way, since the exhausting flow path is provided, the cooling air drawn from the cooling fan is quickly exhausted form the exhaust fan via the exhausting flow path after cooling the enclosing structure, whereby cooling efficiency of the enclosing structure is further increased. In addition, by constructing the exhausting flow path in this way, the inner structure of the projector can be simplified similar to the above-described cooling-air introduction path. Moreover, the cooling air flows on the lower portion of the optical component housing, whereby the optical components, such as a lens and a mirror, disposed inside the housing can be cooled.
In addition, the electro-optical apparatus may preferably have an optical modulation device comprising a pair of substrates and an electro-optical substance clamped between the substrates, and a material having a thermal conductivity of 10 W/mxc2x7K or more may preferably be used for at least one of the substrate. Since the optical modulation device includes such materials, heat generated on the optical modulation device by blocking a part of emitted luminous flux can be efficiently exchanged with the air inside the enclosing structure, and cooling efficiency of the optical modulation device in the enclosing structure can be extremely increased.
According to a another aspect of the present invention, there is provided a projector having a light source, an electro-optical apparatus for forming an image from a luminous flux emitted from the light source according to image information, and a projection lens for enlarging and projecting an image formed by the electro-optical apparatus. The projector may include a structure including an electro-optical apparatus placing portion for placing the electro-optical apparatus and a projection-lens mounting portion for mounting the projection lens, and an enclosing structure including an enclosing member attached to the electro-optical apparatus placing portion to enclose an optical path from the electro-optical apparatus to the projection lens.
The enclosing member can be formed by a box-like member for accommodating therein the electro-optical apparatus. The box-like member made of metal, such as magnesium alloy, may be adopted. In addition, the enclosing member can be adopted which includes a first cover member attached to the electro-optical apparatus placing portion, and a second cover member attached to the opposite side of the electro-optical apparatus placing portion.
Furthermore, the first cover member can be adopted which includes a first side plate disposed on the electro-optical apparatus placing portion so as to surround the electro-optical apparatus, and a second side plate disposed substantially in parallel with the electro-optical apparatus placing portion to cover an end face of the first side plate.
According to the present invention as described above, since the enclosing structure is attached to the electro-optical apparatus placing portion, the enclosing structure for enclosing the electro-optical apparatus can be formed by the electro-optical apparatus placing portion and the enclosing member, whereby dust or the like can be securely prevented from adhering to the electro-optical apparatus. In addition, since the enclosing structure is formed by utilizing the electro-optical apparatus placing portion of the structure, the cost of manufacturing the projector can be reduced, and the projector can be easily reduced in size. In addition, if the enclosing member includes the first cover member and the second cover member and furthermore, if the first cover member is composed of the first side plate and the second side plate, the overall structure of the enclosing structure can be simplified by simplifying the structure of each cover member, the enclosing member can be reduced in size, and the projector can be reduced in size.
In the foregoing, the electro-optical apparatus may preferably include an optical modulation device for modulating the luminous flux according to the image information, and an opening for guiding the luminous flux to the optical modulation device may preferably be formed in the first side plate. In this way, since the opening for guiding a luminous flux to the optical modulation device is formed, the luminous flux emitted from the light source can be suitably modulated by the optical modulation device and emitted from the projection lens, whereby the projector can be positively operated.
A transparent plate may preferably be attached to the opening via a seal material. In this way, since the transparent plate is attached to the opening via a seal material, sealing performance of the inside of the enclosing structure is not damaged, and the luminous flux can be guided to the optical modulation device.
In addition, an incident-side polarizer constituting the optical modulation device is put on the transparent plate. In this way, since the incident-side polarizer is put on the transparent plate, the number of components of the optical modulation device to be attached to the side surface of the color-synthesizing optical system can be reduced, and a mounting structure of the optical modulation device to the color-synthesizing optical system can be simplified.
Furthermore, the projector may preferably include a driving circuit board for driving the optical modulation device, and an electric wiring member for electrically connecting the driving circuit board and the optical modulation device, and a wire insertion hole for inserting thereinto the electric wire member is formed in the first cover member. Since the wire insertion hole is formed in the first cover member, the driving circuit portion of the optical modulation device can be disposed outside the enclosing structure, whereby the enclosing structure can be reduced in size and the projector can be reduced in size.
The first cover member may preferably include a cutout formed by partially cutting out an end of the first side plate; and an engaging part formed on the second side plate and engaging the cutout, and the wire insertion hole is formed as a clearance between the cutout and the engaging part. In such a case, the wire insertion hole may preferably be formed as a clearance between the cutout and the engaging part so as to clamp the electric wiring member by the cutout and engaging part. That is, since the wire insertion hole is formed as a clearance between the cutout and the engaging part, the electric wiring member and the optical modulation device can be taken out of the enclosing structure by removing the engaged portion of the first side plate and the second side plate of the first cover member, whereby maintenance of the optical modulation device and the like can be facilitated.
In addition, the projector may preferably be provided with an elastic packing for sealing the wire insertion hole. In this way, since wire insertion hole in the projector is sealed by the elastic packing, cooling air flowing outside the device does not flow to the inside of the enclosing structure via the wire insertion hole, and air inside the enclosing structure can be always maintained in a clean state.
Furthermore, the electric wiring member may preferably be composed of a flexible wiring board, and a slit for inserting thereinto the flexible wiring board may preferably be formed in the elastic packing. In this way, since the elastic packing is formed in this way, an FPC can be passed through only by forming notches and the like in the rubber packing or the like, whereby the enclosing structure can be simplified.
The above-described aspects can be suitably combined as long as they are consistent with each other, and such combinations can simultaneously provide the action and effect of each of the aspect.